3D Printing for Healthcare is the topic of our next online event, AMA: Healthcare 2026 on June 4th.
At the center of that discussion is work being done not in a clinical setting, but at the intersection of materials science, cellular biology, and additive fabrication.
Dr. Priscila Melo, Lecturer in Bioengineering at Newcastle University and co-founder of JetBio, is advancing 3D tissue models through bioprinting and biofabrication, work aimed squarely at transforming the way new drugs are evaluated before they ever reach a patient.
Looking to deepen your understanding of modern healthcare? Register now for the AMA: Healthcare 2026 online conference and be part of the conversation!
Two-Dimensional Models Are No Longer Sufficient
The standard approach to preclinical drug screening has relied predominantly on two-dimensional cell cultures, monolayers grown on flat substrates that, while cost-effective and technically accessible, fail to replicate the structural and functional complexity of human tissue. The consequences are measurable: approximately 75% of novel drugs that reach the first clinical phase fail, most commonly due to insufficient efficacy or adverse safety profiles that earlier testing did not detect.
The underlying limitation is biological. Human cells exist within a three-dimensional extracellular matrix that governs not only their mechanical environment but also nutrient diffusion, cell-to-cell signaling, and tissue-specific function.
Two-dimensional models eliminate that dimension entirely, producing results that are difficult to translate reliably to in vivo conditions. Three-dimensional in vitro alternatives restore a degree of that physiological complexity, enabling more accurate predictions of compound behavior before clinical exposure.
Regulatory momentum is reinforcing this shift. In 2023, the FDA indicated that validated in vitro models could serve as a basis for human drug trials without requiring animal testing, a position that has accelerated investment and research activity across the field. Europe has since aligned with this direction, and the UK is actively working toward implementing similar standards for specific test categories by 2030.
“If we can eradicate animal testing, for accuracy reasons as much as ethical ones, we should. If right now we can only reduce it, then let’s do that. 3D printing offers a more accurate, viable alternative,” said Melo.
The ReJI Platform and Its Clinical Applications
At Newcastle University, Dr Melo and her colleagues have developed many biofabrication capabilities, including the Reactive Jet Impingement method (ReJI), a proprietary bioprinting technology patented by the university and now being exploited through JetBio.
The system uses microvalves to simultaneously deposit droplets from two cartridges, one containing a hydrogel precursor, the other carrying a cell suspension with a crosslinking agent. The droplets interact mid-air, triggering a rapid chemical reaction that produces a structured, cell-laden construct within milliseconds. The platform supports multiple printing modes, accommodates a range of biomaterials, and has demonstrated compatibility with substrates including synthetic fibres, metals, and biological tissue.
For cardiotoxicity screening, the team bioprinted a cardiac tissue model using a collagen type I, alginate, and fibrin bioink with HL-1 cardiomyocytes at five million cells per millilitre of gel, the highest reported density for this cell type.
The resulting constructs maintained spontaneous contractile activity for up to 21 days, a key improvement over standard two-dimensional culture, where the same cells lose beating function within approximately seven days. Electrical activity, assessed via multi-electrode arrays, became progressively more organised over time and responded appropriately to both pro-arrhythmic and anti-arrhythmic pharmacological agents, validating the model’s potential utility in drug screening workflows.
The same bioink and technology were applied to cartilage repair, where existing approaches, such as ACI, are hindered by poor cell retention at defect sites. By bioprinting chondrocyte-laden hydrogels directly onto Chondro-Gide, a clinically available collagen-based repair patch, the team achieved superior cell distribution and higher expression of cartilage-specific markers, outperforming all other tested conditions.
The findings indicate that integrating bioprinted constructs with established scaffold materials can meaningfully enhance the biological performance of current cartilage therapies.
“The development and adoption of 3D in vitro models in preclinical applications are still in their early stages. Yet these technologies present a valuable opportunity to create models that accurately replicate the in vivo environment and ensure their suitability for downstream analysis.”
The Push to Replace 2D With Something Real
The limitations of two-dimensional cell cultures in preclinical research are well documented and the field is actively building alternatives. Dr. Melo’s work at Newcastle University sits within a broader industry movement toward 3D bioprinted tissue models that more faithfully replicate the in vivo environment. Her ultimate goal is to develop multiphysiological systems capable of replicating systemic interactions, enabling the connection between different tissues and the modelling of comorbidities, which remains one of the greatest challenges in therapeutics development.
CELLINK has made reducing and eliminating animal testing a stated commercial priority, while the EU-funded BRIGHTER project, coordinated by the Institute of Bioengineering of Catalonia, is developing next-generation bioprinting processes specifically designed to reduce reliance on animal models across tissue engineering and regenerative medicine.
Parallel efforts are expanding what these models can cover. Researchers at TU Wien have produced human tissue-on-a-chip constructs using multi-photon lithography. A bioprinted brain vessel model capable of replicating atherosclerotic flow conditions has shown that increasingly complex physiological environments can now be reproduced in vitro, delivering the kind of specificity that makes downstream pharmacological analysis genuinely predictive.
The field is still early, but the direction is clear, and the regulatory environment is beginning to reflect it. Researchers like Dr. Melo continue to address the biological and analytical standards those models will need to meet.
3D Printing Industry is inviting speakers for its 2026 Additive Manufacturing Applications (AMA) series, covering Energy, Healthcare, Automotive and Mobility, Aerospace, Space and Defense, and Software. Each online event focuses on real production deployments, qualification, and supply chain integration. Practitioners interested in contributing can complete the call for speakers form here.
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